did you guys already take a look at XTagFS? this sounds quite similar to the things you are planning...
maybe its possible to join forces or to take a look on how those guys do things -- as xtagfs seems to be under GNU General Public License v2 this shouldn't be so hard ;)

oops, forgot the
oops, forgot the url
http://code.google.com/p/xtagfs/
We didn't know about that,
We didn't know about that, thanks for the link! Seems that it could simplify the tag folder creation :)